# Changes
## 2017/06/07
* Removed an undeclared dependency of MenhirSdk on Unix. (Reported and fixed
by Frédéric Bour.)
## 2017/05/09
* Menhir now always places OCaml line number directives in the generated `.ml`
file. (Until now, this was done only when `--infer` was off.) Thus, if a
semantic action contains an `assert` statement, the file name and line
number information carried by the `Assert_failure` exception should now be
correct. (Reported by Helmut Brandl.)
## 2017/04/18
* Changed Menhir's license from QPL to GPLv2.
MenhirLib remains under LGPLv2, with a linking exception.
* Moved the repository to
[gitlab.inria.fr](https://gitlab.inria.fr/fpottier/menhir/).
* Introduced a new command line switch, `--cmly`, which causes Menhir to
create a `.cmly` file, containing a description of the grammar and
automaton. (Suggested by Frédéric Bour.)
* Introduced a new library, MenhirSdk, which allows reading a `.cmly` file.
The purpose of this library is to allow external tools to take advantage
of the work performed by Menhir's front-end. (Suggested by Frédéric Bour.)
* Introduced new syntax for attributes in a `.mly` file. Attributes are
ignored by Menhir's back-ends, but are written to `.cmly` files, thus
can be exploited by external tools via MenhirSdk. (Suggested by Frédéric Bour.)
* The definition of a `%public` nonterminal symbol can now be split into several
parts within a single `.mly` file. (This used to be permitted only over
multiple `.mly` files.) (Suggested by Frédéric Bour.)
* New functions in the incremental API:
`shifts`, `acceptable`, `current_state_number`.
* New functions in the incremental API and inspection API:
`top`, `pop`, `pop_many`, `get`, `equal`,
`force_reduction`, `feed`, `input_needed`,
`state_has_default_reduction`,
`production_index`, `find_production`.
(Suggested by Frédéric Bour.)
* New module `MenhirLib.ErrorReports`. This module is supposed to offer
auxiliary functions that help produce good syntax error messages.
This module does not yet contain much functionality and is expected
to evolve in the future.
* Incompatible change in the incremental API: the type `env` becomes `'a env`.
* Incompatible change in the incremental API: the function
`has_default_reduction` is renamed `env_has_default_reduction`.
* The type `stack` and the function `stack` in the incremental API are
deprecated. The new functions `top` and `pop` can be used instead to
inspect the parser's stack. The module `MenhirLib.General` is deprecated
as well. Deprecated functionality will be removed in the future.
* Incompatible change in the incremental API: the type of the function
`print_stack` in the result signature of the functor
`MenhirLib.Printers.Make` changes to `'a env -> unit`.
(Anyway, as of now, `MenhirLib.Printers` remains undocumented.)
* Improved the syntax error message that is displayed when a `.mly` file
is incorrect: the previous and next token are shown.
* Fixed a bug where the module name `Basics` was shadowed (that is, if the user's
project happened to contain a toplevel module by this name, then it could not
be referred to from a `.mly` file). (Reported by François Thiré.)
## 2017/01/01
* Add `$MENHIR_STDLIB` as a way of controlling where Menhir looks for the file
`standard.mly`. This environment variable overrides the installation-time
default setting, and is itself overridden by the `--stdlib` command line
switch. (Requested by Jonathan Protzenko.)
* `Makefile` fix: filter out `'\r'` in the output of `menhir --suggest-ocamlfind`,
so that the `Makefile` works when Menhir is compiled as a Windows executable.
(Suggested by Jonathan Protzenko.)
## 2016/12/01
* Updated the Coq back-end for compatibility with Coq 8.6.
(Jacques-Henri Jourdan.)
## 2016/11/15
* Fix in `--only-preprocess-for-ocamlyacc` mode: avoid printing newline characters
inside a `%type` declaration, as this is forbidden by `ocamlyacc`. (Reported by
Kenji Maillard.)
* Fix in `--only-preprocess-for-ocamlyacc` mode: avoid variable capture caused by
`ocamlyacc` internally translating `$i` to `_i`. (Reported by Kenji Maillard.)
## 2016/09/01
* New command line switch `--only-preprocess-for-ocamlyacc`, supposed to print the
grammar in a form that `ocamlyacc` can accept. As of now, this feature is
incomplete (in particular, support for Menhir's position keywords is missing),
untested, and undocumented. It could be removed in the future.
## 2016/08/26
* Fixes in the output of `--only-preprocess`:
* The order of productions is now preserved.
(It was not. This matters if there are reduce/reduce conflicts.)
* `%parameter` directives are now printed. (They were not).
* `%on_error_reduce` directives are now printed. (They were not.)
## 2016/08/25
* `Makefile` fix, undoing a change made on 2016/03/03, which caused installation
to fail under (some versions of?) Windows where dynamic linking is not
supported. (Reported by Andrew Appel.)
## 2016/08/05
* `%on_error_reduce` declarations now have implicit priority levels, so as to
tell Menhir what to do when two such declarations are applicable.
Also, the well-formedness checks on `%type` and `%on_error_reduce` declarations
have been reinforced.
## 2016/06/23
* A small change in the generated code (both in the code and table back-ends) so
as to avoid OCaml's warning 41. The warning would arise (when compiling a
generated parser with OCaml 4.03) because Menhir's exception `Error` has the
same name as the data constructor `Error` in OCaml's pervasive library.
(Reported by Bernhard Schommer.)
## 2016/05/18
* Anonymous rules now work also when used inside a parameterized rule.
(This did not work until now.) When an anonymous rule is hoisted out
of a parameterized rule, it may itself become parameterized. Menhir
parameterizes it only over the parameters that it actually needs.
## 2016/05/04
* In the Coq backend, split the largest definitions into smaller
ones. This circumvents a limitation of vm_compute on 32 bit
machines. This also enables us to perform sharing between
definitions, so that the generated files are much smaller.
## 2016/04/10
* When printing a grammar (which is done by the `--only-preprocess` options),
remove the leading bar `|`, for compatibility with `yacc` and `bison`.
## 2016/03/11
* In the code back-end, generate type annotations when extracting a semantic
value out of the stack. When working with a semantic value of some function
type, OCaml would incorrectly warn that this function does not use its
argument. This warning should now be gone.
## 2016/03/03
* Makefile changes, so as to support `ocamlbuild` 4.03, which seems to have
stricter hygiene rules than previous versions.
## 2015/12/30
* Prevented an incorrect installation that would take place if `USE_OCAMLFIND`
was given during `make all` but not during `make install`. Added a command
line directive `--suggest-ocamlfind`.
## 2015/11/11
* Fixed a severe bug in Menhir 20151110 which (when using the code back-end)
could cause a generated parser to crash. Thanks to ygrek for reporting the
bug.
* The code produced by version `XXXXXXXX` of `menhir --table` can now be linked only
against a matching version of MenhirLib. If an incorrect version of MenhirLib
is installed, the OCaml compiler should complain that
`MenhirLib.StaticVersion.require_XXXXXXXX` is undefined.
## 2015/11/10
* Optimized the computation of `$symbolstartpos`, based on a couple of assumptions
about the lexer. (See the manual.)
## 2015/11/04
* Modified the treatment of `%inline` so that the positions that are computed are
the same, regardless of whether `%inline` is used. This property did not hold
until now. It now does. Of course, this means that the positions computed by
the new Menhir are not the same as those computed by older versions of Menhir.
* Fixed a bug in the treatment of `%inline` that would lead to an incorrect
position being computed when the caller and callee had a variable by the
same name.
* Modified Menhir so as to compute the start and end positions in the exact same
way as `ocamlyacc`. (There used to be a difference in the treatment of epsilon
productions.) Of course, this means that the positions computed by the new
Menhir are not the same as those computed by older versions of Menhir. Added
the keyword `$symbolstartpos` so as to simulate `Parsing.symbol_start_pos()`
in the `ocamlyacc` world. The keyword `$startpos` sometimes produces a position
that is too far off to the left; `$symbolstartpos` produces a more accurate
position.
* Incompatible change of the incremental API: instead of a unit argument, the
entry points (which are named after the start symbols) now require an initial
position, which typically should be `lexbuf.lex_curr_p`.
## 2015/11/03
* Fix-fix-and-re-fix the `Makefile` in an attempt to allow installation under
opam/Windows. Thanks to Daniel Weil for patient explanations and testing.
## 2015/10/29
* MenhirLib is now installed in both binary and source forms.
`menhir --suggest-menhirLib` reports where MenhirLib is installed.
This can be used to retrieve a snapshot of MenhirLib in source form
and include it in your project (if you wish to use `--table` mode, yet
do not wish to have a dependency on MenhirLib).
## 2015/10/26
* Allow `--list-errors` to work on 32-bit machines (with low hard limits).
This should fix a problem whereby the 2015/10/23 release could not
bootstrap on a 32-bit machine.
## 2015/10/23
* New declaration `%on_error_reduce foo`, where `foo` is a nonterminal symbol.
This modifies the automaton as follows. In every state where a production of
the form `foo -> ...` is ready to be reduced, every error action is replaced
with a reduction of this production. (If there is a conflict between several
productions that could be reduced in this manner, nothing is done.) This does
not affect the language that is accepted by the automaton, but delays the
detection of an error: more reductions take place before the error is
detected.
* Fixed a bug whereby Menhir would warn about a useless `%prec` declaration,
even though it was useful. This would happen when the declaration was
duplicated (by inlining or by macro-expansion) and some but not all of
the copies were useful.
* Added `has_default_reduction` to the incremental API.
* Modified the meaning of `--canonical` to allow default reductions to take
place. This implies no loss of precision in terms of lookahead sets,
and should allow gaining more contextual information when a syntax
error is encountered. (It should also lead to a smaller automaton.)
* A brand new set of tools to work on syntax errors.
* New command `--list-errors`, which produces a list of input sentences which
are representative of all possible syntax errors. (Costly.)
* New command `--interpret-error`, which confirms that one particular input
sentence ends in a syntax error, and prints the number of the state in
which this error occurs.
* New command `--compile-errors`, which compiles a list of erroneous sentences
(together with error messages) to OCaml code.
* New command `--compare-errors`, which compares two lists of erroneous sentences
to check if they cover the same error states.
* New command `--update-errors`, which updates the auto-generated comments in
a list of erroneous sentences.
* New command `--echo-errors`, which removes all comments and messages from
a list of erroneous sentences, and echoes just the sentences.
## 2015/10/16
* Additions to the incremental API.
* A `supplier` is a function that produces tokens on demand.
* `lexer_lexbuf_to_supplier` turns a lexer and a lexbuf into a supplier.
* `loop` is a ready-made made main parsing loop.
* `loop_handle` is a variant that lets the user do her own error handling.
* `loop_handle_undo` is a variant that additionally allows undoing the last
few "spurious" reductions.
* `number` maps a state of the LR(1) automaton to its number.
* Incompatible change of the incremental API: renamed the type `'a result`
to `'a checkpoint`. This is a better name anyway, and should help avoid
confusion with the type `'a result` introduced in OCaml 4.03.
## 2015/10/12
* Avoid using `$(shell pwd)` in `Makefile`, for better Windows compatibility.
## 2015/10/05
* Fixed a bug where inconsistent OCaml code was generated when `--table`
and `--external-tokens` were used together. (Reported by Darin Morrison.)
* In `--infer` mode, leave the `.ml` file around (instead of removing it) if
`ocamlc` fails, so we have a chance to understand what's wrong.
## 2015/09/21
* Re-established some error messages concerning the mis-use of `$i` which
had disappeared on 2015/06/29.
## 2015/09/11
* Fixed the mysterious message that would appear when a nonterminal symbol
begins with an uppercase letter and `--infer` is turned on. Clarified the
documentation to indicate that a (non-start) nonterminal symbol can begin
with an uppercase letter, but this is not recommended.
## 2015/08/27
* New option `--inspection` (added last January, documented only now). This
generates an inspection API which allows inspecting the automaton's stack,
among other things. This API can in principle be used to write custom code
for error reporting, error recovery, etc. It is not yet mature and may
change in the future.
## 2015/07/20
* Added the command line options `--unused-token ` and `--unused-tokens`.
## 2015/06/29
* Changed the treatment of the positional keywords `$i`. They are now
rewritten into variables of the form `_i` where `i` is an integer.
Users are advised not to use variables of this form inside semantic
actions.
## 2015/02/11
* Added support for anonymous rules. This allows writing, e.g.,
`list(e = expression SEMI { e })`
whereas previously one should have written
`list(terminated(e, SEMI))`.
## 2015/02/09
* Moved all of the demos to `ocamlbuild` (instead of `make`).
## 2015/01/18
* Incompatible change of the incremental API.
The incremental API now exposes shift events too.
## 2015/01/16
* Fixed a couple bugs in `Makefile` and `src/Makefile` which would cause
compilation and installation to fail with `TARGET=byte`. (Reported
by Jérémie Courrèges-Anglas and Daniel Dickman.)
## 2015/01/01
* Incompatible change of the incremental API.
The entry point `main_incremental` is now named `Incremental.main`.
## 2014/12/29
* Incompatible change of the incremental API.
* The API now exposes reduction events.
* The type `'a result` is now private.
* The type `env` is no longer parameterized.
* `handle` is renamed to `resume`.
* `offer` and `resume` now expect a result, not an environment.
## 2014/12/22
* Documented the Coq back-end (designed and implemented by Jacques-Henri Jourdan).
## 2014/12/15
* New incremental API (in `--table` mode only), inspired by Frédéric Bour.
## 2014/12/11
* Menhir now reports an error if one of the start symbols produces
either the empty language or the singleton language {epsilon}.
* Although some people out there actually define a start symbol that recognizes
{epsilon} (and use it as a way of initializing or re-initializing some global
state), this is considered bad style. Furthermore, by ruling out this case, we
are able to simplify the table back-end a little bit.
## 2014/12/12
* A speed improvement in the code back-end.
## 2014/12/08
* Menhir now requires OCaml 4.02 (instead of 3.09).
## 2014/12/02
* Removed support for the `$previouserror` keyword.
* Removed support for `--error-recovery` mode.
## 2014/02/18
* In the Coq backend, use `'` instead of `_` as separator in identifiers.
Also, correct a serious bug that was inadvertently introduced on
2013/03/01 (r319).
## 2014/02/14
* Lexer fix so as to support an open variant type `[> ...]` within
a `%type` declaration.
## 2013/12/16
* Updated the `Makefile` so that `install` no longer depends on `all`.
* Updated the demos so that the lexer does not invoke `exit 0`
when encoutering `eof`. (This should be more intuitive.)
## 2013/09/11
* Fixed a newline conversion problem that would prevent Menhir from
building on Windows when using ocaml 4.01.
## 2013/03/02
* Switched to ocamlbuild. Many thanks to Daniel Weil for offering
very useful guidance.
## 2013/01/16
* `menhir --depend` was broken since someone added new whitespace in the output
of `ocamldep`. Fixed.
## 2012/12/19
* Fixed a compilation problem that would arise when a file produced
by Menhir on a 64-bit platform was compiled by ocaml on a 32-bit
platform.
## 2012/08/25
* Performance improvements in the computation of various information
about the automaton (module `Invariant`). The improvements will be
noticeable only for very large automata.
## 2012/06/07
* The option `--log-grammar 3` (and above) now causes the `FOLLOW` sets for
terminal symbols to be computed and displayed.
## 2012/05/25
* Added the flag `--canonical`, which causes Menhir to produce a canonical LR(1)
automaton in the style of Knuth. This means that no merging of states takes
place during the construction of the automaton, and that no default reductions
are allowed.
## 2012/01/23
* Fixed a bug whereby a `%nonassoc` declaration was not respected. This
declaration requests that a shift/reduce conflict be reduced in favor of
neither shifting nor reducing, that is, a syntax error must occur. However,
due to an unforeseen interaction with the default reduction mechanism, this
declaration was sometimes ignored and reduction would take place.
## 2012/01/09
* Changes in the (undocumented) Coq back-end so as to match the ESOP 2012
paper.
## 2011/10/19
* The `Makefile` now tests whether Unix or Windows is used (the test is performed
by evaluating `Sys.os_type` under `ocaml`) and changes a couple settings accordingly:
* the executable file name is either `menhir` or `menhir.exe`
* the object file suffix is either `.o` or `.obj`
* Added `--strict`, which causes many warnings about the grammar and about the
automaton to be considered errors.
* The `#` annotations that are inserted in the generated `.ml` file now retain their
full path. (That is, we no longer use `Filename.basename`.) This implies that
the `#` annotations depend on how Menhir is invoked
-- e.g., `menhir foo/bar.mly` and `cd foo && menhir bar.mly` will produce different
results. Nevertheless, this seems reasonable and useful (e.g., in conjunction
with `ocamlbuild` and a hierarchy of files). Thanks to Daniel Weil.
## 2011/10/06
* With the `-lg 1` switch, Menhir now indicates whether the grammar is SLR(1).
## 2011/05/24
* Removed the lock in `ocamldep.wrapper`. It is the responsibility of the user
to avoid interferences with other processes (or other instances of the script)
that create and/or remove files.
## 2011/04/28
* The (internal) computation of the automaton's invariant was broken and has
been fixed. Surprisingly, this does not seem to affect the generated code,
(which was correct,) so no observable bug is fixed. Hopefully no bug is
introduced!
## 2011/04/07
* The grammar description files (`.mly`) are now read in up front and stored in
memory while they are parsed. This allows us to avoid the use of `pos_in` and
`seek_in`, which do not work correctly when CRLF conversion is being performed.
## 2011/04/05
* Fixed a bug in the type inference module (for parameterized non-terminals)
which would cause an infinite loop.
## 2011/01/24
* Fixed a bug that would cause an assertion failure in the generated parser
in some situations where the input stream was incorrect and the grammar
involved the error token. The fix might cause grammars that use the error
token to behave differently (hopefully more accurately) as of now.
## 2009/06/18
* `Makefile` changes: build and install only the bytecode version of MenhirLib
when `TARGET=byte` is set.
## 2009/02/06
* Fixed `ocamldep.wrapper` to avoid quoting the name of the `ocaml` command.
This is hoped to fix a compilation problem under MinGW.
## 2009/02/04
* A `Makefile` fix to avoid a problem under Windows/Cygwin.
* Renamed the `ocaml-check-version` script so as to avoid a warning.
## 2008/09/05
* Ocaml summer project: added `--interpret`, `--table`, and `--suggest-*`.
## 2008/08/06
* Fixed a problem that would cause the code inliner to abort when a semantic
value and a non-terminal symbol happened to have the same name.
* Removed code sharing.
## 2008/06/20
* Removed an incorrect assertion that caused failures (`lr1.ml`, line 134).
## 2007/12/05
* Disabled code sharing by default, as it is currently broken. (See Yann's
message; assertion failure at runtime.)
## 2007/12/01
* Added an optimization to share code among states that have identical
outgoing transition tables.
## 2007/08/30
* Small `Makefile` change: create an executable file for `check-ocaml-version` in
order to work around the absence of dynamic loading on some platforms.
## 2007/05/20
* Made a fundamental change in the construction of the LR(1) automaton
in order to eliminate a bug that could lead to spurious conflicts --
thanks to Ketti for submitting a bug report.
## 2007/05/18
* Added `--follow-construction` to help understand the construction of the
LR(1) automaton (very verbose).
## 2007/05/11
* Code generation: more explicit qualifications with `Pervasives` so as
to avoid capture when the user redefines some of the built-in operators,
such as `(+)`.
* Added a new demo (`calc-param`) that shows how to use `%parameter`.
## 2007/03/22
* `Makefile` improvements (check for `PREFIX`; bootstrap in bytecode now
also available). Slight changes to `OMakefile.shared`.
## 2007/02/15
* Portability fix in `Makefile` and `Makefile.shared` (avoided `which`).
## 2006/12/15
* Portability fix in `Makefile.shared` (replaced `&>` with `2>&1 >`).
## 2006/06/23
* Made a slight restriction to Pager's criterion so as to never introduce
fake conflict tokens (see `Lr0.compatible`). This might help make conflict
explanations more accurate in the future.
## 2006/06/16
* Fixed bug that would cause positions to become invalid after inlining.
## 2006/06/15
* Fixed `--depend` to be more lenient when analyzing `ocamldep`'s output.
* Added `--raw-depend` which transmits `ocamldep`'s output unchanged (for
use in conjunction with `omake`).
## 2006/06/12
* Fixed bug that would cause `--only-preprocess` to print `%token` declarations
also for pseudo-tokens.
* Fixed bug that caused some precedence declarations to be incorrectly
reported as useless.
* Improved things so that useless pseudo-tokens now also cause warnings.
* Fixed bug that would cause `%type` directives for terminal symbols to
be incorrectly accepted.
* Fixed bug that would occur when a semantic action containing `$i` keywords
was inlined.
## 2006/05/05
* Fixed problem that caused some end-of-stream conflicts not to be reported.
* Fixed Pager's compatibility criterion to avoid creating end-of-stream conflicts.
## 2006/04/21
* Fixed problem that allowed generating incorrect but apparently well-typed
Objective Caml code when a semantic action was ill-typed and `--infer` was
omitted.
## 2006/03/29
* Improved conflict reports by factoring out maximal common derivation contexts.
## 2006/03/28
* Fixed bug that could arise when explaining a conflict in a non-LALR(1) grammar.
## 2006/03/27
* Changed count of reduce/reduce conflicts to allow a comparison
with `ocamlyacc`'s diagnostics.
* When refusing to resolve a conflict, report all diagnostics before dying.
## 2006/03/18
* Added display of `FOLLOW` sets when using `--log-grammar 2`.
* Added `--graph` option.
* Fixed behavior of `--depend` option.
## 2006/01/06
* Removed reversed lists from the standard library.